Preheating/precooling heat exchanger

ABSTRACT

A preheating/precooling heat exchanger including a preheating/precooling exchanger and an evaporator. The preheating/precooling exchanger has an intake and an exhaust port for compressed air to come in and go out. The intake is connected with an intake duct circulated inside the preheating/precooling exchanger to communicate with the evaporator. A condensing pipe is circulated inside the evaporator for heat exchange between the compressed air and a coolant in the condensing pipe and for condensing the vapor in the compressed air into water drops. The evaporator has an inlet and an outlet. The inlet is connected to the intake duct of the preheating/precooling exchanger, whereby the compressed air can go from the intake duct into the evaporator. The outlet communicates with the preheating/precooling exchanger, whereby the compressed air can flow back into the preheating/precooling exchanger.

BACKGROUND OF THE INVENTION

The present invention is related to a preheating/precooling heat exchanger with higher heat exchange efficiency and reduced volume.

In a conventional compressed air purifying system, a wind-cooling drier is disposed for cooling and drying the compressed air so as to prevent the system from being affected by the humidity and temperature of the compressed air. FIG. 3 shows a conventional wind-cooling drier including a precooler 6, an air heat exchanger 7, an evaporator 8 and a condenser 9. The temperature of the compressed air is first lowered to normal temperature by the precooler 6. Then the compressed air goes into the air heat exchanger 7 to slightly precool the compressed air and remove part of the vapor. Then the compressed air further goes into the evaporator 8 for heat exchange between the compressed air and the coolant. The condenser 9 sends the coolant into the evaporator 8 to lower the temperature of the compressed air to dew point within 2° C.˜10° C. Most of the vapor contained in the compressed air will be condensed into water drops which are separated and exhausted by an air/water separator 81. Finally, the cooled and dried compressed air is sent out for operation of the drier.

The conventional wind-cooling drier includes the precooler 6, air heat exchanger 7, evaporator 8 and the condenser 9 so that the direr has big volume and heavy weight. Accordingly, the drier will occupy too much room of the compressed air purifying system. Moreover, in operation, all the components of the drier will generate heat to ascend the environmental temperature. As a result, the air going into the precooler 6will be overheated and the cooling efficiency will be lowered. Therefore, the power of the evaporator 8 and the condenser 9 must be increased to lower the temperature of the air. Accordingly, the burden on the evaporator 8 and the condenser 9 is increased. This often leads to the problem of skip in a high-temperature environment such as in a summer day.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide a preheating/precooling heat exchanger including a preheating/precooling exchanger and an evaporator. The preheating/precooling exchanger has an intake and an exhaust port for compressed air to come in and go out. The intake is connected with an intake duct circulated inside the preheating/precooling exchanger to communicate with the evaporator. A condensing pipe is circulated inside the evaporator for heat exchange between the compressed air and a coolant in the condensing pipe and for condensing the vapor in the compressed air into water drops. The evaporator has an inlet and an outlet. The inlet is connected to the intake duct of the preheating/precooling exchanger, whereby the compressed air can go from the intake duct into the evaporator. The outlet communicates with the preheating/precooling exchanger, whereby the compressed air can flow back into the preheating/precooling exchanger. The compressed air cooled by the evaporator will further flow back into the preheating/precooling exchanger. Therefore, the temperature of the original high-temperature compressed air in the intake duct of the preheating/precooling exchanger 1 will be lowered. Accordingly, the temperature of the compressed air going into the evaporator is lowered so that the evaporator can reduce the temperature of the compressed air to dew point without great power. Therefore, the condensing power is enhanced to effectively lower the burden on the coolant compressor. Accordingly, the skip of the heat exchanger caused by too high environmental temperature can be avoided.

It is a further object of the present invention to provide the above preheating/precooling heat exchanger. The compressed air cooled by the evaporator will further flow back into the preheating/precooling exchanger. Accordingly, the temperature of the cooled compressed air is neutralized with the temperature of the high-temperature compressed air in the intake duct. Therefore, the compressed air going from the evaporator into the preheating/precooling exchanger is backheated and the compressed air sent out from the exhaust port has a suitable temperature. Therefore, the problem of dewing of the pipeline can be avoided.

It is still a further object of the present invention to provide the above preheating/precooling heat exchanger. The compressed air cooled by the evaporator will further flow back into the preheating/precooling exchanger. Therefore, the condensing power is enhanced and the condensing system can be simplified to reduce the volume of the entire heat exchanger.

According to the above objects, the preheating/precooling heat exchanger of the present invention includes a preheating/precooling exchanger and an evaporator. The preheating/precooling exchanger has an intake and an exhaust port for compressed air to come in and go out. The intake is connected with an intake duct circulated inside the preheating/precooling exchanger to communicate with the evaporator. A condensing pipe is circulated inside the evaporator for heat exchange between the compressed air and a coolant in the condensing pipe and for condensing the vapor in the compressed air into water drops. The evaporator has an inlet and an outlet. The inlet is connected to the intake duct of the preheating/precooling exchanger., whereby the compressed air can go from the intake duct into the evaporator. The outlet communicates with the preheating/precooling exchanger, whereby the compressed air can flow back into the preheating/precooling exchanger.

The present invention can be best understood through the following description and accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the layout of the components of the present invention;

FIG. 2 shows that the compressed air is cooled and dried by the present invention; and

FIG. 3 shows the layout of the components of a conventional wind-cooling drier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Please refer to FIGS. 1 and 2. The preheating/precooling heat exchanger of the present invention includes a preheating/precooling exchanger 1, an evaporator 2 and a coolant compressor 3. At least one fan 11 is disposed on outer side of the preheating/precooling exchanger 1. The preheating/precooling exchanger 1 has an intake 12 and an exhaust port 13. The intake 12 is connected with an intake duct 121 circulated inside the preheating/precooling exchanger 1 to communicate with the evaporator 2. A condensing pipe 21 is circulated inside the evaporator 2. The coolant compressor 3 supplies coolant for the condensing pipe 21. The evaporator 2 has an inlet 22 and an outlet 23. The inlet 22 is connected to the intake duct 121 of the preheating/precooling exchanger 1, whereby the compressed air goes from the intake duct 121 into the evaporator 2. The outlet 23 communicates with the preheating/precooling exchanger 1, whereby the compressed air can flow back into the preheating/precooling exchanger 1.

The high-temperature compressed air goes from the intake 12 along the intake duct 121 into the preheating/precooling exchanger 1 and circulates within the preheating/precooling exchanger 1. The fan 11 precools the compressed air. Then the compressed air goes through the intake duct 121 into the evaporator 2, whereby a heat exchange takes place between the compressed air and the coolant in the condensing pipe 21. The temperature of the compressed air is lowered to the dew point within 2° C.˜10° C. Most of the vapor in the compressed air is condensed into water drops which are separated and exhausted by an air/water separator 4. Then the cooled compressed air further goes from the outlet 23 of the evaporator 2 back into the preheating/precooling exchanger 1. Not only the cooled compressed air reduces the temperature of the original high-temperature compressed air in the intake duct 121 of the preheating/precooling exchanger 1, but also the temperature of the cooled compressed air is neutralized with the temperature of the high-temperature compressed air in the intake duct 121. Accordingly, the compressed air going from the evaporator 2 into the preheating/precooling exchanger 1 is backheated. Then dry compressed air with suitable temperature is sent out from the exhaust port 13 of the preheating/precooling exchanger 1.

The compressed air cooled by the evaporator will further flow back into the preheating/precooling exchanger 1. Therefore, the temperature of the original high-temperature compressed air in the intake duct 121 of the preheating/precooling exchanger 1 will be lowered. Accordingly, the temperature of the compressed air going into the evaporator 2 is lowered so that the evaporator 2 can reduce the temperature of the compressed air to dew point without great power. Therefore, the condensing power is enhanced to effectively lower the burden on the coolant compressor 3. Accordingly, the skip of the heat exchanger caused by too high environmental temperature can be avoided.

Moreover, the compressed air cooled by the evaporator 2 will further flow back into the preheating/precooling exchanger 1. Accordingly, the temperature of the cooled compressed air is neutralized with the temperature of the high-temperature compressed air in the intake duct 121. Therefore, the compressed air going from the evaporator 2 into the preheating/precooling exchanger 1 is backheated and the compressed air sent out from the exhaust port 13 has a suitable temperature. Therefore, the problem of dewing of the pipeline can be avoided. Besides, the compressed air cooled by the evaporator will further flow back into the preheating/precooling exchanger 1. Therefore, the condensing power is enhanced and the condensing system can be simplified to reduce the volume of the entire heat exchanger.

The above embodiment is only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiment can be made without departing from the spirit of the present invention. 

1. A preheating/precooling heat exchanger comprising a preheating/precooling exchanger and an evaporator, the preheating/precooling exchanger having an intake and an exhaust port for compressed air to come in and go out, the intake being connected with an intake duct circulated inside the preheating/precooling exchanger to communicate with the evaporator, a condensing pipe being circulated inside the evaporator for heat exchange between the compressed air and a coolant in the condensing pipe and for condensing the vapor in the compressed air into water drops, the evaporator having an inlet and an outlet, the inlet being connected to the intake duct of the preheating/precooling exchanger, whereby the compressed air can go from the intake duct into the evaporator, the outlet communicating with the preheating/precooling exchanger, whereby the compressed air can flow back into the preheating/precooling exchanger.
 2. The preheating/precooling heat exchanger as claimed in claim 1, wherein at least one fan is disposed on outer side of the preheating/precooling exchanger.
 3. The preheating/precooling heat exchanger as claimed in claim 1, wherein a coolant compressor supplies coolant for the condensing pipe of the evaporator.
 4. The preheating/precooling heat exchanger as claimed in claim 1, wherein the evaporator includes an air/water separator for separating and exhausting the water drops condensed from the vapor in the compressed air. 